LU stands for “Lock-Up”. It’s the solenoid that controls signal pressure to the torque converter lock-up clutch.

I'll never unsubscribe to this channel because even if we wait months it's never a disappointment.

These teardowns are therapeutic somehow. Not sure how or why, but they seem to add calmness and peace to interesting content.

when you say, I don't know how much interest this video will get, I want to scream; PLEASE don't quit making your vids! Quit doubting yourself Pal. Your expression of technique & knowledge is well appreciated...even valued. Thanks again for having me and the others along.

The sheer scale of everything is amazing. Thank you for taking the time to film and describe your work.

I think you’re on the right track as far as the actual transmission problems. The valve body definitely looked bad when you separated it. It doesn’t take much as you know to cause issues with any kind of rust or debris in there. Torque converter should be a quick tear down and will tell the rest of the story. I hope you decide to make a part 2 to this. I’ve been missing your videos. Good to see you back.

There was one problem with that transmission, the extra tool found inside. I vote to make this a series. Cool stuff.

I love this channel, no stupid intro no fake drama and yelling. Just someone who knows exactly what they are doing so bada$$!

The amount of work involved making each component and the fact it all works is incredible to me.

Couldn’t imagine the machining hours in that assembly

Every time I see things like this, I am just amazed by the amount of engineering put into transmissions. Simply amazing.

The ability of big gear to put in like >15 000 hours of work in absolute hell conditions yet still look like new will never cease to amaze me. It seems to me that 90% of major failures boil down to human error in some way, shape or form.

It has always been a good day when he has uploaded a new video

This type of video is why I love this channel. To see the amount of engineering, the amount of precision machining, the levels of complexity all to get one 40 ton Cat haul truck transmission to accurately shift through its gears and move huge amounts of dirt around mines and construction sites. It is a beautiful thing. And then we have our host's dry as hell well look at this shit here monolog, it's a great combination.

LU usually stands for Lock Up, at least in Allison transmissions, which is the friction clutch that engages the pump and the turbine of the converter together, making it to spin at the same speed of the engine. I dont even know if this transmission is equipped with that

This Big stuff is just fascinating and very interesting. As a journeyman mechanic this is enormous yet complex. I also watch Western Truck and Tractor Repair and all of the heavy duty work that Warren does there. I've even worked a day with him. Great guy!! Thanks soooo much for going through this large transmission it sure give perspective to the work load that this equipment has to do!! All the best from Canada

Man the quality of every part in this thing. It certainly costs tens of thousands just to make it.

“I can’t stand it. I gotta look in here.” Well said. It’s irresistible.

Ya, keep going. It will be interesting to actually find out why they pulled it out of service. Another great video.

I love this channel eventhough I'll never own or work on any type of equipment like this. It's just so incredibly fascinating. I just wish the content was MORE frequent. The bit about the damn crickets was hilarious.

I love the content you make, none of the inflated bs or sponsors you see in other videos, just straight to the point. I look forward to each one you make

Please continue with the tear down and evaluation! Super interesting to see the 'inside' story on these machines! Thanks!!!

Man. Idk why but I just have to watch your videos. I never owned, or never will own any construction equipment like that. But your knowledge and authenticity is special on YT so i'll always support.

I enjoy the tear downs, we all learned what the guts look like in one of these things, something I DIDNT know yesterday. We appreciate it👍🏼

Please Dont Stop Making Your Videos. I have watched everyone you have posted. We understand that making these videos take a lot of time, but we will always be here to watch them. thanks for taking time out of your day to show us.

it's amazing the engineering and design that goes into these super heavy-duty machines. Time tested.

That was cool. Everytime i rebuild a transmission everyone freaks out like its some magical box that shouldnt be touched. Their so easy yet so complex.

Had a really shitty day, finally sat down to eat and watch a couple videos and BAM! Made my day seeing you posted a new one! Always fascinating seeing the scale and quality of these parts and pieces that make up these amazing machines. Really appreciate your efforts every time. Great job!

did a couple of these in school super simple and they never seem to break. would be sweet to see what actually went wrong

Great video. I love working in transmissions and this was fascinating to me. As to the failure... I'm wondering if they had a failure and did a DIY repair where they failed to really clean anything (explaining the obvious material found at the beginning), and just replaced the frictions. That would explain the overheated steel - that was from the previous failure. They put it back together, and put the solenoid in the wrong port, then gave up when it failed on them again. Based on the yellow washer and the free socket, I'm betting this was a DIY repair by whoever owned this thing. It would explain a lot. PLEASE upload the rebuild video. I want to see this thing go back together!!!

You really have the perfect mindset/attitude for dealing with big equipment; respect for it without being intimidated by the scale/size of the parts and assemblies that are involved. Thanks for the video! If you make ‘em, we’ll watch ‘em.

Thank you for another excellent video - no b.s. just solid commentary and showing how to get things done. Thank you for your time and efforts that you have taken in all of your videos sir!

I did see that socket fall out when you lifted the case. I didn't know at the time it was a socket but I did say, "what was that"?

That eight seventy one is one thought cookie. Haliburton has hundreds, nay thousands of those engines all over the world. Great video, thanks for making it. PS, the crumple zone on the Bus was impressive! Best wishes.

Thank you for bringing us along. I sure hope you continue filming this series. Very interesting!

Just imagine the size of this in a 100ton haul truck, I find it very interesting

Your videos are never a disappointment for people who are interested in heavy machinery and how it works .

I am still surprised there aren't a couple million subscribers to this channel ! His destruction videos are epic. But the teardowns of this big machinery is beyond compare ! Speaks in clear calm English . I look forward to every video on here ! 🌵

love your mannerisms and dry humor. don't mind the gaps in content, upload when you get q chance, we'll be here

the metallic particles you found at the start are perfectly normal for a transmission of that size, as long as it is "dust" and not "needles" you shouldnt worrry about that. every piece looked brand new, im willing to bet that's not where the problem is, if there is any

Great video. The only thing wrong in the transmission was a socket! It looks brand new inside, except for water. Please keep going.

Please keep going with the videos on this machine. Maybe we'll find the failure.

A new KT upload is a great day

Most educational tear down channel in my opinion

Very impressive clean professional workmanship! Enjoy the steam clean standards too. Can't wait for the next bit. Much appreciated...

That's insane seeing the size of the clutches, steels, etc. The center support on that thing weighs more than the entire case on the 4r70w's I mess with.... just so cool to see it's essentially the same damn thing, just a helluva lot bigger. Keep 'em coming man- we appreciate it!!

Watching you and Warren are not only enjoyable but you two tell it like it is. And informative as well. Thanks for the lesson and a look in side. Keep them coming.

Another great video, please keep going with the driveline series, the size and simplicity of the process is fascinating.

Keep it going. We need to see what the issue is, and we need to see if you move the down shift solenoid back to the middle spot. I enjoy your videos.

Love the teardowns! When I was a kid I would ask for tractor manuals from Central Tractor I don't know why but I wanted to see how they worked. Still prefer my paper manuals to the PDFs that the OEMs put out these days.

Never a dull video from you and yes, you do know what you're doin'

Man that is so satisfying to watch the power washer clean all that grime off. These things are beast, I could never imagine rebuilding one, which is why I love your videos.

never stop making videos ,we will wait months for your next one, also that’s some amazing engineering ,thanks for sharing

Good stuff! Massive Transmission...all seemed clean, no bits and pieces other than the fine glitter, at least there weren't teeth of gears in the bottom or something! Definitely tear into that bad boy...loving seeing heavy equipment internals and stuff Keep em coming!!!!

“I’ve taken this entire transmission apart and there’s nothing wrong with it” I fucking love it. You put out some of the best content on KZfaq

As a mechanic working on Automotive applications I have to say watching somebody else disassemble a transmission of this scale gives me heart palpitations LOL love the content bud. Keep it up, it's love to see that transfer case

Your content is really enjoyable to watch. It's a nice slow and relaxing pace with a person who knows what he's talking about. Its a nice learning experience. Your doing excellent Mr. Please, if you can, keep up the amazing work.

What a great video. This gave me flashbacks of working at a farm implement dealer in the late 90’s. A Powershift transmission sounds simple until you start tearing them apart and have parts scattered across the shop. I appreciate the no nonsense commentary. I especially liked the Cricket comment, I’m sure some people would think you could control the cricket’s chirping. That looks like a bunch of expensive parts if you had to buy them from CAT. Looking forward to seeing the rest torn apart. Thanks for taking us along on the adventure.

Would definitely love to see more tear down on this unit! I’m no machinery guy but I really enjoy your videos!

It’s amazing to think about the massive amount of torque and pressure that unit is under during use. Someone stuck with a loaded truck can grenade the entire system. Nice work.

it just turned into a good day thanks to KT 3406 E

LU = lock up If the Converter has a clutch in it, that solenoid may be to control it. As an automotive transmission rebuilder I am just guessing. I found this video super interesting ! appreciate all your other videos !

Thanks for taking the time to post up these videos. They mean different things to different people. I for one like to listen to your dulcet voice and no bullsh!t take on life. Reminds me of the old folks from the Okie branch of my family.

The control module for the gearshift is sometimes called an XYZ switch

I know zero about these big beautiful machines, but I am enthralled by your vids. Love your sense of humor too. Thanks for sharing!

I would love to see more videos like this on the hauler truck!

God bless. Mr 3406 is back to entertain us all

Very cool. Its great to see inside these big machines. Great organization too, with so many pieces it would be easy to mix stuff up.

Once again you took the time to show me something I knew nothing about. Great stuff- thanks. You're always concise, articulate and easy to understand. Anyone taught by you would be lucky.

Great video it’s amazing these engineers can invent stuff like this but can’t make anything easy to work on lol 😂 love watching thanks for sharing

Dry sense of humor 😂 , Best tear down and rebuild channel , keep the content coming .

Keep doing the tear down! It's very satisfying watching you take things apart, explain how everything works and ultimately finding out whats the root cause of the issue. I'm all for seeing you tear everything apart, even if there's nothing wrong with it.

How you can disassemble everything and put it back together is astonishing! An engineer with a degree on the wall could never do it. Well done and thank you for sharing!

I hope you never quit making videos they are awesome buddy

Interesting to see no shims for setting any clutch pack clearance. Make sure to pressure check your clutch pack pistons when you put it back together.

My favorite part was outside the wind kicked up and you said here we go with this shit again! Priceless! Had me laughing

Hi 👋🏻 buddy. I’m no engineer of any kind but love engines especially trains 😊 I find your tear downs very interesting and your sense of humour makes it perfect 👍🏻 Cheers Stevie 🏴󠁧󠁢󠁥󠁮󠁧󠁿

Wow! 7.2k views in 3 hours!! Dude! Way to go. You're definitely doing everything right.

L/U stands for torque converter lock up clutch. At least in the power shift world I came from. (Allison Transmission)

You are the bravest man on KZfaq this week!!!! Amazing engineering! ❗❗❗❗❗❗❗

That's where my socket went! Just paying it forward because I found a 8mm one in the oil pan of my old Toyota 20R once.

You said Shaft so many times, I started singing your theme song 🎵. “Who is the man who checks the planetary gears and sets. KT3406E! You damn right!!!!”

I always enjoy your videos. You are probably one of the best out there.

Stunning to acknowledge the brilliant minds that design machinery like this. Through much trial and error, over many years, the final product is put to use. To think every single piece, part, component had to be designed, tested, by someone, not some computer, is awesome.

KT, if those are anything like a normal automatic, those clutch disks do NOT appreciate water AT ALL. They will come off what they are mated to. Also, when you replace them, I recommend you soak them in fluid before installing them in a clean unit. Soaking them will bring them to their standard, in-use, stack height, so you can get your clearances and stack heights correct. I would also check the book for all of those load springs to ensure their heights are within spec. When you are looking at the planetary gears, check them thoroughly to ensure the load washers between them and the housing are still in good shape. I bet those are fairly costly to replace if they are bad. I have watched you while assembling something and you are exceptionally particular with cleanliness, this is one crazy aspect where that OCD is well worth it my friend - surgically clean is best. (LOL) I really appreciate watching what you do - KEEP 'EM COMING!!! (Looking forward to you and that valve body)

“These crickets are in here raising hell. You’ll just have to live with it.” 😂 instant 👍🏻 just for that.

Always great content. I'd love to see the full tear down.

I agree with others here. It is never a disappointment. Always interesting. We all learn.

May I say, the pressure washing result was exquisite! I love your deadpan delivery - it makes for great videos. Also man that is a complicated setup. I'd have a tought time memorizing all the gazillion parts. What will you keep and what will you replace? Great video sir! And, yeah, keep on a goin'!

That whole mess looked as if it had been very recently gone through. That shift solenoid in the wrong hole has me wondering.

KT... love your stuff! You are brillant beyond your years and without any formal training or mentor... Truely outstanding. I have watched every video and I will continue to do so. When my long awaited ship comes in, I will commission you to build me a 3406.

Keep it up. I really enjoy your videos

Goddamn my day has been made! He has uploaded!!

Lots of interest in these kind of videos. Please continue

Them clutch packs look brand new! Awesome job, great video! Please keep posting more videos!!

My armchair expert opinion - seeing the forbidden glitter so close to solenoids - either valvebody screens/filters are clogged or solenoids are full of that stuff (or checkvalves, or anything around really). Either way, not enough pressure would cause slipping (and explain that discoloration)... sadly, if that glitter had any chance to make it around bearings, they might be toast too. Clean magnetic filter is sus, probably was taken apart, flushed, socket was left as a lucky charm or sacrifice to planetary gods... and when it was reassembled (with fat invoice included) it started to slip in one of the gears. Immediately destined for sale.

You found your long lost 10mm at 14:24!!! Long time subscriber. Like many have said, great chan. Always brightens my weekend when you post. Thank you.

Another great video! It always amazes me how unbelievably complex these transmissions are!

KT3406E, I really appreciate all Your videos! I always learn something new every time I watch Your videos! Even tho I don't do a lot of work on this type of diesel equipment, its always interests me how they work and operate! When it comes to this stuff You are the best of the best (IMHO) Thanks so much for sharing this with us and look forward to Your next video! Cheers DC.

Really cool video. I'm looking foward for the next one!